HPLC determination of sulfamethazine in milk using surface-imprinted silica synthesized with iniferter technique

A new method for the synthesis of sulfamethazine-imprinted polymer on the surface of silica via quasi-living radical polymerization and the application of the resulting polymer in determination of the SMZ in milk is developed. In the synthesis, initiator-transfer agent-terminator (iniferter) was immobilized on the silica surface using chemical reagents with good availability. The imprinting polymerization was initialized by the silica-supported iniferter under the UV radiation. The molecularly imprinted polymer (MIP) layer grafted on the silica surface was constructed by using sulfamethazine (SMZ) as the template, methacrylic acid (MAA) as the functional monomer and ethylene dimethacrylate (EDMA) as cross-linker. The resulting MIP-silica has good selectivity for SMZ and high column efficiency in the HPLC analysis. The result demonstrated that the SMZ-imprinted polymer was grafted on the silica surface successfully. Under the optimized HPLC condition, the MIP-silica has been used for the determination of SMZ in milk. The method was linear over the concentration range of 0.1–50 μg mL−1 with correlation coefficient R > 0.999. The detection limit for SMZ was 25 ng mL−1. The recoveries were above 78% at the spiked concentration of 0.024, 0.24 and 0.48 μg mL−1.